This invention concerns a mesh pattern eraser for an endoscope which can eliminate the mesh pattern observed when a bundle of optical fibers arranged in a regular pattern is used for an image guide or image transferring means.
Recently a medical endoscope has been widely used which makes it possible to observe or diagnose an affected part, etc. in the human body without necessity of incision by inserting a long and narrow and flexible inserting member into the body through the mouth or to perform medical treatment using forceps and scalpel.
Also, in the industrial field, the industrial endoscope is used for the inspection of damaged parts of the inner wall of the piping in a plant or foreign matter sticking to the inner wall.
The medical endoscope is normally constructed with a soft inserting member which can be inserted through a crooked passage, and is so designed that a subject such as an affected part can be illuminated by an illuminating means which irradiates light from the end of the inserting member. An image is-formed at one end face of the image guide, constituting an image transferring means made of a flexible optical fiber bundle, by means of the image-forming optical system, transferred to the other end face at hand through the image guide, and enlarged and observed through the eye lens system.
But since the image guide means uses a bundle of fibers arranged in a regular pattern as an image transferring means, the spaces between the adjacent fibers become dark because they do not transfer the light, and a mesh pattern is observed when the image is observed through the eye lens system, thus making it difficult to see the image and also the high-frequency component of the mesh pattern makes the image indistinct.